Switching device

Abstract

The invention relates to a switching device (100). The switching device (100) comprises two or more current paths (13, 23, 33) via which energy can be supplied for a downstream load (53). An electronic interruption unit (11) and a mechanical switch (12) are arranged in series in each of the current paths (13, 23, 33). Each of the current paths (13, 23, 33) has an assigned decentralized control unit (111, 211, 311), which is designed to actuate the electronic interruption unit (11, 21, 31).

Description

[0001] Description

[0002] Switchgear

[0003] The present invention relates to a switching device with two or more current paths, via which a power supply for a downstream electrical load can be effected, wherein an electronic interruption unit and a mechanical switch are arranged in series in each of the current paths. The present invention also relates to an operating method of the switching device.

[0004] Switching devices for switching the power supply of a downstream electrical load are well known. For example, motor starters are used to control and protect three-phase motors directly on the mains. A distinction is made between direct-on-line starters and soft starters. Direct-on-line starters switch a mains voltage directly to the motor, whereas soft starters have the option of limiting the effective voltage at the motor for the start-up period or of slowly increasing it by means of phase control. See the two graphics on page 21C-6 in: Siemens AG, Fundamentals of Low-Voltage Controls and Technology, 2008, http: / / www.siemens.de / lowvoltage / grundlagen.

[0005] As a rule, today's motor starters are implemented either by means of a corresponding connection of contactors, see DE 10 2008 026 376 Al (Siemens AG) December 02, 2009, or as hybrid starters, see DE 10 2012 214 814 Al (Siemens AG) February 27, 2014, where "hybrid" refers to a combination of robust relay technology and wear-free semiconductor technology. In both designs, a central control unit controls the switching elements of the motor starter to assume either a current-conducting or a current-blocking state.For this purpose, the central control unit receives measured values ​​for current, voltage or temperature from sensors that monitor current paths leading through the motor starter, from which the central control unit can deduce whether acceptable operating conditions prevail in the current paths, so that electrical energy can be conducted through the current paths and the switching elements to the motor, or whether unacceptable operating conditions such as a short circuit or a prolonged overload exist, so that the current conduction through the current paths must be interrupted by means of the switching elements.

[0006] The object of the present invention is an improved switching device.

[0007] This object is achieved according to the invention by a switching device having the features specified in claim 1. This object is also achieved according to the invention by a method having the features specified in claim 9.

[0008] The switching device has two or more current paths via which energy can be supplied to a downstream load. The switching device can be, for example, a motor starter, a soft starter or a contactor. The load can have an inductive behavior, e.g. an electric motor, a resistive behavior, e.g. an electric heater, or a capacitive behavior, e.g. a rectifier. The current paths conduct the load current intended for the electrical load from a mains-side connection device of the switching device through the switching device to a load-side connection device of the switching device. An electronic interruption unit and a mechanical switch are arranged in series in each of the current paths, i.e. the current to supply the load is conducted via both the electronic interruption unit and the mechanical switch.Preferably, the electronic interruption unit is assigned to the network-side connection device and the mechanical switch is assigned to the load-side connection device.

[0009] An electronic interruption unit is an electronic switch that performs the function of an electromechanical switch but has no moving parts. The electronic interruption unit can be switched by semiconductor-based switching elements into a high-resistance state of the switching elements to prevent current flow or a low-resistance state of the switching elements to allow current flow in the current path. Semiconductor-based switching elements such as field-effect transistors (FETs), MOSFETs (silicon, gallium nitride, silicon carbide), IGBTs, bipolar transistors or diodes are used for this purpose. In addition to a semiconductor switch, an electronic interruption unit has a protection element for the semiconductor switch.

[0010] A mechanical switch, also known as a mechanical isolating contact unit, is an electromechanical switch that can be switched into a current-blocking state by opening contacts to prevent current flow in the current path, or into a current-conducting state by closing the contacts to allow current flow in the current path. The mechanical switch is a mechanical isolating contact system, in particular with isolating properties in accordance with the relevant standards for low-voltage circuits (voltages of up to 1000 volts AC or up to 1500 volts DC), with the contacts of the mechanical isolating contact system being connected in series with the electronic interruption unit. The mechanical switch can, for example, be designed as a relay.

[0011] Each current path is assigned a decentralized control unit which is designed to control the electronic interruption unit; the switching state of an electronic interruption unit (current-conducting or current-blocking) is therefore controlled by the assigned decentralized control unit.

[0012] The switching device according to the invention can be connected to an electrical supply line of an electrical load and used to switch and / or protect the electrical load; therefore, the switching device according to the invention can alternatively also be referred to as a switching and protection device . Protecting the electrical load by the switching device serves to protect the electrical load and the supply line leading to the electrical load from impermissibly high currents . A supply line of an electrical load is an electrical line via which the load is supplied with electrical energy . Examples of the use of a switching device are applications as circuit breakers, contactors , relays and motor starters, i.e. a switching device for starting an electric motor .

[0013] The method according to the invention serves to operate a switching device with two or more current paths, via which power is supplied to a downstream load. An electronic interruption unit and a mechanical switch are arranged in series in each of the current paths. The method comprises controlling the electronic interruption unit of a current path by a decentralized control unit assigned to this current path.

[0014] The invention is based on the finding that a multi-controller architecture for an electronic switching and protective device, i.e. a switching and protective device equipped with electronic interruption units, offers advantages in short-circuit protection: Since the current and / or voltage values ​​from which the short circuit is detected do not first have to be sent over a long transmission path to a central control unit and the switching commands from there back to the electronic interruption unit, but rather the current and / or voltage values ​​are analyzed and the switching commands are generated in a decentralized control unit, which is physically located close to the current / voltage sensor and the electronic interruption unit and can be reached via short transmission paths, a switching reaction to an incoming hazard such as a short circuit or overload can take place significantly faster than before.By distributing the control function across multiple decentralized control units, smaller and more cost-effective control units can be used than with an architecture with a single central control unit. By cleverly distributing the functions between the central control unit and the decentralized control units, less powerful controllers can be used compared to a single-controller solution.

[0015] In the event of a failure of a decentralized control unit, the central control unit takes over control of the electronic interruption unit assigned to the failed decentralized control unit. If the decentralized control unit detects a sensor failure, the decentralized control unit sends a shutdown command directly to the assigned electronic interruption unit so that the unsafe operating condition is ended as quickly as possible. In addition, the decentralized control unit reports this information—that a sensor error exists—to the central control unit, which then triggers actions in the other decentralized control units.

[0016] This design of a switching device with a decentralized control unit per current path can be referred to as a "multi-controller" architecture; such an architecture is the core of the present invention. It serves as the basis for a modular structure both on the HW development side and on the FW development side (FW = firmware, HW = hardware). It can be used, for example, for a 3-phase motor starter or for a (3+N) infrastructure switch.

[0017] The invention provides a switching device that offers short-circuit strength for very high grid connection power, short-circuit protection even for very high current rises, and is flexible with regard to the expansion of protection and measurement functions. In particular, the decentralized control units enable flexibly adjustable short-circuit limits for each phase or each current path. Advantageous embodiments and further developments of the invention are specified in the dependent claims.

[0018] According to a preferred embodiment of the invention, the switching device has a central control unit designed to communicate with the decentralized control units for coordinating the electronic interruption units and the mechanical switches in the two or more current paths. One advantage of this is that the central control unit receives information on measured values ​​in the current paths and switching states of the electronic interruption units from the decentralized control units and, based on this information, can send additional on or off commands to the decentralized control units if necessary.

[0019] According to a preferred embodiment of the invention, the central control unit is designed as a separate physical electronic component of the switching device. An advantage of this is that the firmware running in the decentralized control units can be identical, thus making different runtimes for processing firmware algorithms unlikely.

[0020] According to a preferred embodiment of the invention, the central control unit is integrated in the form of a firmware stack into at least one of the decentralized control units. The firmware stack provides the full functionality of the central control unit for phase coordination, i.e., for coordination of the electronic interruption units and the mechanical switches in the two or more current paths of the switching device. One advantage of this is that hardware is eliminated, namely a separate physical electronic component for a central control unit.

[0021] The central control unit is provided as a separate controller or as a firmware module running on one of the decentralized control units. This central control unit then receives all information on measured variables and the status of the corresponding other power paths and can then send on or off commands to the other decentralized control units if necessary.

[0022] The central control unit sends information, e.g., switching commands, parameter sets, and commands for activating additional functions, to the decentralized control units and receives information, e.g., measured values, error states, and parameter sets, from the decentralized control units. The central control unit can be configured to activate the power supply of the decentralized control units.

[0023] According to a preferred embodiment of the invention, a sensor is assigned to each current path for measuring a current in the current path and / or a voltage in the current path against a reference voltage of another current path, wherein the sensor is designed so that the measured values ​​can be transmitted to the decentralized control unit assigned to the current path. For this purpose, the sensor can have an interface for wired or wireless transmission. One advantage of this is that the current operating conditions in the current paths and the state of the energy supply for a downstream load can be recorded.

[0024] According to a preferred embodiment of the invention, the switching device has an interface for parameterizing the switching device. One advantage of this is that the switching device can be easily parameterized using an external parameterizing device, either wired or wirelessly.

[0025] According to a preferred embodiment of the invention, it is provided that the decentralized control units communicate directly with one another. In other words, the decentralized control units are designed to communicate with one another. For example, two digital signals (input and output) can be exchanged, i.e., sent and received, between two decentralized control units. For example, the information of a current zero crossing in one decentralized control unit can be transmitted to one or more of the other decentralized control units. Direct communication can occur in various ways.

[0026] A first possibility is data communication via a bus system, e.g. using SPI (= Serial Peripheral Interface) or a serial interface, e.g. UART (= Universal Asynchronous Receiver Transmitter), for exchanging information such as measured variables and states between the decentralized control units in the form of binary character strings, without involving the central control unit. This information exchange is necessary, for example, when implementing the central control functions in the decentralized control units in the form of a firmware module.

[0027] With the second option, only individual digital signals with a rising edge, a falling edge and a duration of the signal level are transmitted as information carriers. With these digital signals, which are generated by the decentralized control units, information can be encoded in the rising edge, the falling edge and the duration of the signal level. Which information, e.g. overcurrent error, overload error, current zero crossing, is assigned to the respective signal can be specified in advance by the central control unit in a coding specification that is made available to the decentralized control units. An example of this would be zero current detection in one of the decentralized control units. If a current zero crossing is detected, the level of a digital signal is changed from low to high, or high to low.This signal is detected by the other decentralized control units, and actions can be triggered accordingly. The information about the zero crossing in one decentralized control unit can be relevant for the other decentralized control units. The transmission system for transmitting digital signals via digital signal lines between the decentralized control units avoids delays that can occur in a bus system due to the communication medium and the processing of the information.

[0028] According to a preferred embodiment of the invention, an insulation barrier is formed between each two current paths. One advantage of this is that electrical safety is improved.

[0029] According to a preferred embodiment of the invention, the decentralized control units each have configurable analog modules. The analog modules can be, for example, comparators or operational amplifiers. These analog modules integrated into the decentralized control units can be configurable via firmware, which can reduce the complexity of the externally required hardware. An advantage of this embodiment of the invention is that it ensures a high degree of flexibility and simplifies the manufacture and repair of the switching device.

[0030] According to a preferred embodiment of the invention, the decentralized control unit, the electronic interruption unit, and the sensor, each assigned to a current path, form a protection and measurement module. Such a module can also be referred to as a protection and measurement cell. A module of this type can perform other functions in addition to short-circuit protection:

[0031] • Shunt-based current measurement with very high bandwidth >500kHz: The module can incorporate a shunt to measure the current in the current path. This allows the switching device to detect and respond to a short circuit relatively quickly.

[0032] • Measuring the mains voltage between two current paths and measuring the switch voltage applied across the electronic interruption unit: The module can have one or more voltmeters for measuring voltages. This can detect a short circuit. The central control unit can use the mains voltage and switch voltage to determine the voltage applied to the load side of the control unit. This information can be used, for example, when restarting an electric motor.

[0033] • Providing the measured values ​​via a communication interface of the module. The module can have a communication interface for this purpose. The measured values ​​can be provided to the central control unit via this communication interface.

[0034] The core of the protection and measuring module is the decentralized control unit, i.e. a controller that can implement protection and additional functions. The protection and measuring modules or the decentralized control units of a switching device are coordinated by a higher-level controller, the central control unit. Actions of a decentralized control unit can be triggered by the central control unit via communication links and interfaces, e.g. switching on a power semiconductor, executing diagnostic functions, etc. Measured values ​​or states can also be transmitted from the decentralized control units to the central control unit via communication links and interfaces.

[0035] According to a preferred embodiment of the invention, the method comprises the following steps: measuring a current and / or a voltage in the current path; sending the measured values ​​to the decentralized control unit assigned to the current path; sending control commands to the electronic interruption unit of a current path based on the measured values ​​measured in the current path. One advantage of this is that the current operating conditions in the current paths and the state of the power supply for a downstream load can be recorded.

[0036] According to a preferred embodiment of the invention, the switching device has signal lines via which the decentralized control units or the protection and measurement modules can be synchronized, e.g., for simultaneous sampling of measured values ​​in all protection and measurement modules. For this purpose, the switching device can have dedicated signal lines, or the synchronization signals required for synchronization can be sent via the existing communication connections between the central control unit and the decentralized control units.

[0037] According to a preferred embodiment of the invention, the central control unit sends synchronization signals to the decentralized control units, whereby the decentralized control units can be synchronized. By means of the synchronization signals received from the decentralized control units, the decentralized control units can synchronize their calculation steps and / or actions with one another, so that simultaneous execution of the calculation steps and / or actions is ensured. The accuracy of the synchronization of the decentralized control units can be in the range of nanoseconds. Calculation steps can relate to the processing of an algorithm which, for example, runs in the form of a computer program on a decentralized control unit. Actions comprise switching an electronic interruption unit at a switching time and scanning devices of the analog peripherals at a scanning time.A synchronization signal can be formed by a falling and / or rising edge of a digital signal.

[0038] According to a preferred embodiment of the invention, the method comprises the following steps: sending information regarding the measured values ​​and the control commands from the decentralized control units to a central control unit of the switching device; coordinating, by the central control unit, the electronic interruption units and the mechanical switches in the two or more current paths on the basis of the received information. One advantage of this is that the central control unit receives all information regarding measured values ​​and the status in the corresponding other current paths and can, if necessary, send switching on or off commands to the other decentralized control units.

[0039] In the following, the invention is explained with the aid of the accompanying drawing. It shows schematically and not to scale

[0040] Fig. 1 shows a typical circuit arrangement of a switching device;

[0041] Fig. 2 shows a schematic structure of a known switching device;

[0042] Fig. 3 shows a schematic structure of a switching device according to the invention;

[0043] Fig. 4 shows an embodiment of a switching device according to the invention;

[0044] Fig. 5 is a flow diagram of a short-circuit shutdown;

[0045] Fig. 6 shows an example of a short-circuit shutdown;

[0046] Fig. 7 is a flow diagram of an operational switch-on;

[0047] Fig. 8 is a flow diagram of a first mode of operational activation; and

[0048] Fig. 9 is a flow chart of another mode of operational activation;

[0049] Fig. 10 shows an embodiment of direct communication via a bus system; and

[0050] Fig. 11 shows an embodiment of direct communication using digital signals. Fig. 1 shows a typical circuit arrangement of a switching device 1 arranged in a three-phase electrical supply line 51, 52, divided into a mains-side supply line 51 and a load-side supply line 52, via which electrical energy is conducted from an electrical supply network 50 with three outer conductors L1, L2, L3 to an electrical load 53, e.g., an electric motor or an electric heater. The switching device 1 has mains-side connection devices 131, 231, 331 and load-side connection devices 132, 232, 332, by means of which the switching device 1 is connected to the electrical supply line 51, 52.

[0051] Fig. 2 shows a schematic view of the internal structure of a conventional switching device 1 which can be used in a circuit arrangement as shown in Fig. 1. The switching device 1 has three current paths 13, 23, 33, via which one of the outer conductors LI, L2, L3 of the three-phase supply network 50 can be routed. For this purpose, the switching device 1 has network-side connection devices 131, 231, 331, e.g. screw terminals or spring-loaded terminals, with which the network-side ends of the current paths 13, 23, 33 can be electrically connected to the network-side supply lines 51 of the supply network 50. For this purpose, the switching device 1 also has load-side connection devices 132, 232, 332, e.g. B. screw terminals or spring clamp terminals, with which the load-side ends of the current paths 13, 23, 33 can be electrically connected to the load-side supply lines 52 of the load 53.

[0052] In each of the current paths 13, 23, 33, an electronic interruption unit 11, 21, 31 and a mechanical switch 12, 22, 32 are arranged in series, wherein an electrical current with a current direction from the network-side connection devices 131, 231, 331 to the load-side connection devices 132, 232, 332 flows first through the electronic interruption units 11, 21, 31 and then through the mechanical switches 12, 22, 32. Between the mains-side connection devices 131, 231, 331 and the electronic interruption units 11, 21, 31, current and / or voltage sensors 41, 42, 43 are arranged in the current paths 13, 23, 33, which are suitable for measuring the current I and / or the electrical voltage U in the current paths 13, 23, 33.

[0053] The switching device 1 has a central control unit 2 equipped with a processor 3, which can receive measured values ​​from the current and / or voltage sensors 41, 42, 43 via data lines 410, 420, 430 and can send switching commands via communication connections 14, 24, 34 to the electronic interruption units 11, 21, 31 and via a control line 16 to a switching mechanism 15 that acts on the mechanical switches 12, 22, 32. The measured values ​​from the current and / or voltage sensors 41, 42, 43 can be present as analog signals or as digital data. Data lines 410, 420, 430 are understood here to mean any transmission means, both transmission lines, e.g. cables, and wireless transmission means, e.g. B. NFC (= Near Field Communication), Bluetooth, WLAN (= Wireless Local Area Network).

[0054] The control unit 2 can analyze the received measured values ​​of the current and / or voltage sensors 41, 42, 43 and, based on the analysis, determine whether the current and / or voltage values ​​are within a normal and proper range or within an unacceptable range, e.g., within an overload range, a short-circuit range, etc. The control unit 2 can set a current-blocking state or a current-conducting state of the electronic interruption units 11, 21, 31 and the mechanical switches 12, 22, 32 by issuing appropriate switching commands. In normal operation, the control unit 2 can switch a supply of electrical energy to the load by issuing appropriate switching commands.For example, when interrupting a current path during normal operation, an unwanted arc between the contacts of the mechanical switch can be avoided by first switching the electronic interruption unit to block the current and only then opening the mechanical switch. If current and / or voltage values ​​are within an unacceptable range, switching device 1 can protect the load downstream of switching device 1 from damage by interrupting the current paths by issuing appropriate switching commands.

[0055] The control unit 2 can be configured either wired or wirelessly. It is also possible for one or more parameters of the control unit 2 to be adjustable via a potentiometer on the control unit 2.

[0056] Fig. 3 shows, with a relatively low level of detail, the schematic structure of a switching device 100 according to the invention, which can be used in a circuit arrangement as shown in Fig. 1. Compared to the conventional switching device 1 shown in Fig. 2, the switching device 100 according to the invention is characterized in that each electronic interruption unit 11, 21, 31 is assigned a decentralized control unit 111, 211, 311. In the illustrated embodiment, the switching device 100 has, in addition to the decentralized control units 111, 211, 311, a central control unit 200, which coordinates between the decentralized control units 111, 211, 311. Apart from the decentralized control units 111, 211, 311, the structure of the switching device 100 according to the invention shown in Fig. 3 is thus comparable to the structure of the conventional switching device 1 shown in Fig. 2; the control units shown in Fig.The circuit arrangement shown in Figure 1 is possible with a switching device 100 according to the invention as well as with a conventional switching device 1.

[0057] The switching device 100 has three current paths 13, 23, 33, over which each of the outer conductors LI, L2, L3 of the three-phase supply network 50 can be routed. For this purpose, the switching device 1 has network-side connection devices 131, 231, 331, e.g., screw terminals or spring-loaded terminals, with which the network-side ends of the current paths 13, 23, 33 can be electrically connected to connecting lines 51 of the supply network 50. For this purpose, the switching device 1 also has load-side connection devices 132, 232, 332, e.g., screw terminals or spring-loaded terminals, with which the load-side ends of the current paths 13, 23, 33 can be electrically connected to connecting lines 52 of the load 53.

[0058] In each of the current paths 13, 23, 33, an electronic interruption unit 11, 21, 31 and a mechanical switch 12, 22, 32 are arranged in series, wherein an electrical current with a current direction from the network-side connection devices 131, 231, 331 to the load-side connection devices 132, 232, 332 flows first through the electronic interruption unit 11, 21, 31 and then through the mechanical switches 12, 22, 32. Between the mains-side connection devices 131, 231, 331 and the electronic interruption units 11, 21, 31, current and / or voltage sensors 41, 42, 43 are arranged in the current paths 13, 23, 33, which are suitable for measuring the current I and / or the electrical voltage U in the current paths 13, 23, 33.

[0059] Each of the electronic interruption units 11, 21, 31 is assigned a decentralized control unit 111, 211, 311. These decentralized control units 111, 211, 311 receive measured values ​​from the current and / or voltage sensors 41, 42, 43 via data lines 410, 420, 430 and send switching commands to the electronic interruption units 11, 21, 31 via communication connections 116, 216, 316. The measured values ​​from the current and / or voltage sensors 41, 42, 43 can be present as analog signals or as digital data. Data lines 410, 420, 430 are understood here to mean any transmission medium, both transmission lines, e.g., cables, wires, and wireless transmission media; e.g., NEC, Bluetooth, WLAN. The switching commands can be simple digital signals (with two different states: low - high).The decentralized control units 111, 211, 311 can analyze the received measured values ​​of the current and / or voltage sensors 41, 42, 43 and, on the basis of the analysis, determine whether the current and / or voltage values ​​are within a normal and proper range or within an unacceptable range, e.g., within an overload range, a short-circuit range, etc. The decentralized control units 111, 211, 311 can, by means of appropriate switching commands, set the electronic interruption units 11, 21, 31 to a current-blocking state or a current-conducting state. During normal operation, the decentralized control units 111, 211, 311 can switch a supply of electrical energy to the load by means of appropriate switching commands.For example, when interrupting a current path during normal operation, an undesirable arc between the contacts of the mechanical switch can be avoided by first switching the electronic interruption unit 11, 21, 31 to block the current and only then opening the mechanical switch 12, 22, 32. If current and / or voltage values ​​are within an unacceptable range, the switching device 100 can protect the load connected downstream of the switching device 100 from damage by interrupting the current paths using appropriate switching commands.

[0060] The switching device 100 also has a central control unit 200 equipped with a processor 201. The central control unit 200 is connected to the decentralized control units 111, 211, 311 via communication links 140, 240, 340; in this way, the central control unit 200 can coordinate the control behavior of the decentralized control units 111, 211, 311 through control commands.

[0061] The central control unit 200 communicates separately with each decentralized control unit 111, 211, 311. This communication serves, on the one hand, to transmit information and, on the other hand, to synchronize all decentralized control units 111, 211, 311, so that coordinated switching of all electronic interruption units 11, 21, 31 is possible if necessary.

[0062] According to an alternative embodiment, it can also be provided that the decentralized control units 111, 211, 311 communicate directly with each other. For example, two digital signals (input and output) can be exchanged, i.e., sent and received, between the decentralized control units 111, 211, 311. For example, the information of a current zero crossing at one decentralized control unit can be transmitted to one or more of the other decentralized control units.

[0063] According to a first embodiment, which is outlined in Fig. 3, the mechanical switches 12, 22, 32 are not controlled by the decentralized control units 111, 211, 311, but by the central control unit 200. For this purpose, the central control unit 200 sends control commands via a control line 160 to a switching mechanism 150 that acts on the mechanical switches 12, 22, 32.

[0064] According to an alternative embodiment, the mechanical switches 12, 22, 32 are controlled by the decentralized control units 111, 211, 311. In this case, the central control unit 200 sends switching commands, which are intended to cause the mechanical switches 12, 22, 32 to be switched, to the decentralized control units 111, 211, 311 via communication links 140, 240, 340. The decentralized control units 111, 211, 311, in turn, send control commands to the switching mechanism 150 or directly to a switching actuator of the respective mechanical switch 12, 22, 32.

[0065] A variant of the switching device 100 is the relocation of one or more functions of the central control unit 200 to one of the decentralized control units 111, 211, 311. For this purpose, the functions can be integrated as software components into one of the decentralized control units 111, 211, 311. The coordination function can also be implemented decentrally, e.g., integrated into one or more of the decentralized control units 111, 211, 311. The coordination function can be implemented as a software component, e.g., as firmware.

[0066] The control unit 2 can be parameterized either wired or wirelessly.

[0067] Fig. 4 shows an embodiment of a switching device 100 according to the invention with a relatively high level of detail. The switching device 100 has three current paths 13, 23, 33, via which one of the outer conductors LI, L2, L3 of a three-phase supply network 50 can be routed. For this purpose, the switching device 100 has network-side connection devices 131, 231, 331, e.g. screw terminals or spring-loaded terminals, with which the network-side ends of the current paths 130, 230, 330 can be electrically connected to connecting lines 51 of the supply network 50. For this purpose, the switching device 100 also has load-side connection devices 132, 232, 332, e.g. B. screw terminals or spring terminals, with which the load-side ends of the current paths 13, 23, 33 can be electrically connected to connecting lines 52 of the load 53.

[0068] In each of the current paths 13, 23, 33, a protection and measuring module 170, 270, 370 and a mechanical switch 12, 22, 32 are arranged in series, wherein an electrical current with a current direction from the network-side connection devices 131, 231, 331 to the load-side connection devices 132, 232, 332 flows first through the protection and measuring modules 170, 270, 370 and then through the mechanical switches 12, 22, 32.

[0069] The protection and measurement modules 170, 270, 370 each have a grid-side connection device 123, 223, 323 and a load-side connection device 124, 224, 324, whereby the protection and measurement modules 170, 270, 370 are connected to the current paths 13, 23, 33. The grid-side connection devices 123, 223, 323 and the load-side connection devices 132, 232, 332 are each electrically connected to one another by a load current line 130, 230, 330. The protection and measurement modules 170, 270, 370 each have a current sensor 114, 214, 314 for measuring the current I in the load current lines 130, 230, 330 and an electronic interruption unit 11, 21, 31, which are connected in series in the load current lines 130, 230, 330.

[0070] The protection and measuring modules 170, 270, 370 each have a decentralized control unit 111, 211, 311, which is assigned to the electronic interruption unit 11, 21, 31 of the protection and measuring modules 170, 270, 370. These decentralized control units 111, 211, 311 receive measured values ​​from the current sensors 114, 214, 314 via data lines 115, 215, 315 and send switching commands via communication links 116, 216, 316 to the electronic interruption units 11, 21, 31. The decentralized control units 111, 211, 311 can analyze the received measured values ​​from the current sensors 41, 42, 43 and, based on the analysis, determine whether the current values ​​are within a normal and proper range or within an unacceptable range, e.g., within an overload range, a short-circuit range, etc.The decentralized control units 111, 211, 311 can each set a current-blocking state or a current-conducting state of the electronic interruption units 11, 21, 31 by means of appropriate switching commands. In normal operation, the decentralized control units 111, 211, 311 can switch a supply of electrical energy to the load by means of appropriate switching commands. For example, when interrupting a load current line 130, 230, 330 in normal operation, an undesirable arc between the contacts of the mechanical switch can be avoided by first switching the electronic interruption unit to block the current and only then opening the mechanical switch. If current and / or voltage values ​​are within an unacceptable range, the switching device 100 can protect the load connected close to the switching device 100 from damage by interrupting the current paths by means of appropriate switching commands.

[0071] The switching device 100 also has a central control unit 200 equipped with a processor 201. The central control unit 200 is connected to the protection and measuring modules 170, 270, 370 via communication links 140, 240, 340. The protection and measuring modules 170, 270, 370 each have an interface 112, 212, 312, which receives incoming signals from the central control unit 200 and sends signals from the protection and measuring modules 170, 270, 370 to the central control unit 200. For this purpose, the interfaces 112, 212, 312 are each connected to the corresponding decentralized control unit 111, 211, 311 via a communication connection 117, 217, 317.In this way, the central control unit 200 can coordinate the control behavior of the decentralized control units 111, 211, 311 by means of control commands; on the other hand, data and information which the central control unit 200 requires for its coordination tasks can be transmitted from the protection and measurement modules 170, 270, 370 to the central control unit 200, respectively.

[0072] The central control unit 200 can also send control commands via a control line 160 to a switching lock 150 acting on the mechanical switches 12, 22, 32.

[0073] The control unit 2 can be parameterized either wired or wirelessly.

[0074] Fig. 5 shows a flow diagram of a short-circuit shutdown in a switching device according to the invention. A first step 501 marks a state in which current flows in one of the plurality of current paths of a switching device according to the invention, hereinafter referred to as "the current path". In step 502, a current sensor determines measured values ​​of the current intensity of the current flowing in the current path and sends the current measured values ​​to the decentralized control unit assigned to it. In addition, a voltage sensor determines voltage measured values ​​of the voltage applied to the current path and also sends the measured voltage measured values ​​to the decentralized control unit assigned to it. In step 503, the decentralized control unit receives the measured current and voltage measured values ​​from the sensors. In step 504, the decentralized control unit compares the current measured values ​​with a permissible value range or a current limit value In mHere, two different cases are considered: In a first case 1, the decentralized control unit determines in step 505 that the current measurement values ​​are within a permissible value range or below the current limit value Ii im Therefore, this measuring cycle is terminated in step 506 with the result that no action is necessary and the next measuring cycle is awaited.

[0075] In a second case 2, the decentralized control unit determines in step 507 that the current measured values ​​are above a permissible value range or above the current limit value Ii im(trigger threshold). The decentralized control unit therefore determines that a short circuit has occurred. In step 508, the decentralized control unit immediately issues a switch-off command directly to the electronic interruption unit that is connected to the current path so that the short circuit is ended as quickly as possible. In step 509, triggered by the received switch-off command, the electronic interruption unit changes to a current-blocking state. In step 510, the decentralized control unit reports the information that a short circuit in the current path has been detected and that a switch-off command has been sent to the electronic interruption unit that is connected to the current path to the central control unit. In step 511, the central control unit triggers actions by the other decentralized control units, e.g.a change of the electronic interruption units connected to the other current paths of the switching device into a current-blocking state. The central control unit thus coordinates the opening of the electronic interruption units in the other current paths 13, 23, 33 and preferably also of the mechanical switches.

[0076] A similar procedure can also be used for asymmetry detection. With a symmetrical load, the sum of the currents in the current paths (phases) is approximately zero. When asymmetry is detected, the currents in all current paths are measured, summed and compared with a threshold value band: the sum of the measured values ​​should be within a value band of +-x amperes around the zero point. A typical value is x = 2, whereby the value can be set on the switching device (parameterization). If the sum of the measured values ​​is within the threshold value band, no action is necessary. However, if the sum of the measured values ​​is outside the threshold value band, this is detected as an asymmetry and a shutdown command is sent to the decentralized control units, which then initiate a current-blocking switching of the electronic interruption units.

[0077] Fig. 6 illustrates an example of a short-circuit disconnection in a switching device according to the invention. The upper part of the graph shows a time course of current I S w and mains voltage U G R, which are present in one current path of the plurality of current paths of the switching device, hereinafter referred to as "the current path". The middle part of the graph shows a time course of a gate signal S G , which is applied to a gate of a gate-controlled semiconductor switch of the electronic interruption unit, which is connected in the current path. The lower part of the graph shows a time course of an output signal S c a current comparator which measures the current I present in the current path of the switching device S w with a current limit value Ii im compares .

[0078] At a time tO, at which the sinusoidal curve of the mains voltage has a zero crossing and a voltage period begins, current flows through the current path of the switching device. This is made possible by the fact that the electronic interruption unit, which is connected to the current path, is in a current-conducting state, as is a mechanical switch connected in series with the electronic interruption unit, which is not considered further here. The electronic interruption unit has a semiconductor switch with a gate, e.g. a transistor or a thyristor. Depending on the control of the gate, the electronic interruption unit can be put into a current-conducting or a current-blocking operating state. At time tO, the electronic interruption unit is in a current-conducting state, since a control signal S G > 0 is present .

[0079] At the time tl > tO a short circuit is triggered in the current path (phase) under consideration. The current I S w then increases until a given current limit value In m is exceeded. Exceeding the current limit In m is detected by a comparator which continuously checks whether the current Isw exceeds the current limit value In m exceeds ; at the time t2 of the exceedance, the output signal S c of the comparator from a value S c = 0 to a value S c > 0 .

[0080] The decentralized control unit assigned to the current path in question sends an instantaneous switch-off command directly to the electronic interruption unit connected to the current path. Triggered by the switch-off command, the electronic interruption unit changes from the current-conducting state to a current-blocking state by switching the gate signal S G of a value S G > 0 to a value S G = 0 . As a result, the current in the current path decays to 0 A and the short circuit is extinguished .

[0081] Fig. 7 shows a flow diagram of an operational shutdown in a switching device according to the invention. In step 701, the central control unit sends a shutdown command to the decentralized control units. In step 702, after receiving the shutdown command, the decentralized control units wait until the current is approximately 0 A, with an adjustable hysteresis of +- 0.5 A (parameterization). In step 703, the decentralized control units send the shutdown command to the electronic interruption units.

[0082] Fig. 8 shows a flowchart of a first mode of operational switching in a switching device according to the invention. In the first step 801, the central control unit sends a switch-on command to the decentralized control units. In step 802, after receiving the switch-on command, the decentralized control units immediately send the switch-on command to the electronic interruption units.

[0083] Fig. 9 shows a flow diagram of an alternative mode of operational switching on in a switching device according to the invention. In the first step 811, the central control unit sends a voltage phase angle at which switching is to take place to the decentralized control units. In step 812, the decentralized control unit evaluates the input voltage present at the input terminals of the switching device and issues the switch-on command to the electronic interruption units when the voltage phase angle is reached.

[0084] Fig. 10 shows a further embodiment of a switching device 100 according to the invention. The switching device has all the features of the switching device shown in Fig. 4 - the mechanical switches 12, 22, 32 are not shown in Fig. 10 to simplify the illustration - but additionally has a bus-based communication system (short: bus system) with a bus line 5 between the protection and measuring modules 170, 270, 370, which each have a decentralized control unit 111, 211, 311. The data communication via the bus system, e.g. using SPI or a serial interface such as e.g. UART is used to exchange information such as measured variables and states of the decentralized control units 111, 211, 311 with each other in the form of binary character strings, without involving the central control unit 200.For example, when implementing the central control functions in the decentralized control units 111, 211, 311 in the form of the FW module, this information exchange is necessary.

[0085] Fig. 11 shows a further embodiment of a switching device 100 according to the invention. The switching device has all the features of the switching device shown in Fig. 4 - the mechanical switches 12, 22, 32 are not shown in Fig. 11 to simplify the illustration - but additionally has a transmission system for transmitting digital signals via digital signal lines 6, 7, 8 between the protection and measuring modules 170, 270, 370, which each have a decentralized control unit 111, 211, 311. A first digital signal line 6 is used to transmit signals from the decentralized control unit 111 of the first protection and measuring module 170 to the decentralized control units 211, 311 of the second and third protection and measuring modules 270, 370.A second digital signal line 7 is used for signal transmission from the decentralized control unit 211 of the second protection and measurement module 270 to the decentralized control units 111, 311 of the first and third protection and measurement modules 170, 370. A third digital signal line 8 is used for signal transmission from the decentralized control unit 311 of the third protection and measurement module to the decentralized control units 111, 211 of the first and second protection and measurement modules 170, 270.

[0086] Only individual digital signals with a rising edge, a falling edge and a duration of the signal level are transmitted as information carriers via the digital signal lines 6, 7, 8. In these digital signals, which are generated by the decentralized control units 111, 211, 311, information can be encoded in the rising edge, the falling edge and the duration of the signal level. Which information, e.g. overcurrent error, overload error, current zero crossing, is assigned to the respective signal can be specified in advance by the central control unit 200 in a coding rule that is made available to the decentralized control units 111, 211, 311. An example of this would be zero current detection in one of the decentralized control units 111, 211, 311.If one of the decentralized control units 111, 211, 311 detects a current zero crossing, the detecting decentralized control unit 111, 211, 311 changes the level of a digital signal from low to high or from high to low. This signal level change is detected by the other decentralized control units 111, 211, 311, and actions can be triggered accordingly by the decentralized control units 111, 211, 311. The information of the zero crossing by a decentralized control unit 111, 211, 311 can be relevant for the other decentralized control units 111, 211, 311. The transmission system for transmitting digital signals via digital signal lines 6, 7, 8 between the decentralized control units 111, 211, 311 avoids delays that can occur in a bus system due to the communication medium and the processing of the information.

Claims

Patent claims 1. Switching device (100) with two or more current paths (13, 23, 33) via which a power supply for a downstream load (53) can take place, wherein in the current paths (13, 23, 33) in each case an electronic interruption unit (11) and a mechanical switch (12) are arranged in series, characterized in that the current paths (13, 23, 33) are each assigned a decentralized control unit (111, 211, 311) which is designed to control the electronic interruption unit (11, 21, 31).

2. Switching device (1) according to claim 1, comprising a central control unit (200) which is designed to coordinate the electronic interruption units (11, 21, 31) and the mechanical switches (12, 22, 32) in the two or more current paths (13, 23, 33) to communicate with the decentralized control units (111, 211, 311).

3. Switching device (1) according to claim 2, wherein the central control unit (200) is designed as a separate physical electronic component of the switching device (100) or is integrated in the form of a firmware module in at least one of the decentralized control units (111, 211, 311).

4. Switching device (100) according to one of the preceding claims, wherein the current paths (13, 23, 33) are each assigned a sensor (41, 42, 43) for measuring a current intensity in the current path (13, 23, 33) and / or a voltage in the current path (13, 23, 33) against a reference voltage of another current path (13, 23, 33), wherein the sensor is designed such that the measured values ​​can be transmitted to the decentralized control unit (111, 211, 311) assigned to the current path (13, 23, 33).

5. Switching device (100) according to one of the preceding claims, wherein the decentralized control units (111, 211, 311) are designed to communicate directly with one another.

6. Switching device (100) according to one of the preceding claims, wherein the decentralized control units (111, 211, 311) each have configurable analog modules.

7. Switching device (100) according to claim 4, wherein the decentralized control unit (111, 211, 311), the electronic interruption unit (11, 21, 31) and the sensor (41, 42, 43), which are each assigned to a current path (13, 23, 33), form a module (170, 270, 370).

8. Switching device (1) according to one of claims 2 to 7, wherein the central control unit (200) is designed to provide synchronization signals for the decentralized control units (111, 211, 311).

9. Method for operating a switching device (100) with two or more current paths (13, 23, 33), via which a power supply for a downstream load (53) takes place, wherein in the current paths (13, 23, 33) in each case an electronic interruption unit (11) and a mechanical switch (12) are arranged in series, characterized by the following step: controlling the electronic interruption unit (12) of a current path (13, 23, 33) in each case by a decentralized control unit (111, 211, 311) which is assigned to this current path (13, 23, 33).

10. The method according to claim 9, wherein a central control unit (200) of the switching device (100) sends synchronization signals to the decentralized control units (111, 211, 311), by means of which the decentralized control units (111, 211, 311) can be synchronized.

11. Method according to one of claims 9 or 10, comprising the following steps: Measuring a current and / or a voltage in the current path (13, 23, 33); Sending the measured values ​​to the decentralized control unit (111, 211, 311) assigned to the current path (13, 23, 33); Sending control commands to the electronic interruption unit (11, 21, 31) of a current path (13, 23, 33) on the basis of the measured values ​​measured in the current path.

12. Method according to one of claims 9 or 10, comprising the following steps: Sending information regarding the measured values ​​and the control commands from the decentralized control units (111, 211, 311) to a central control unit (200) of the switching device (100); Coordinating, by the central control unit (200), the electronic interruption units (11, 21, 31) and the mechanical switches (12, 22, 32) in the two or more current paths (13, 23, 33) on the basis of the received information.

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